The present invention relates to an electronic unit.
Japanese Unexamined Utility Model Application Publication No. 4-20217 discloses a planar coil device having a sheet coil, a heat radiation plate and a core. Specifically, the sheet coil is formed by an insulation sheet and a foil conductor provided on the insulation sheet to form a coil. The heat radiation plate is insulated from the sheet coil. The sheet coil and the heat radiation plate are stacked together and fitted in the core.
There is known an electronic unit such as a transformer using a double-sided substrate such as a thick copper substrate. The thick copper substrate has a structure that patterned copper plates are bonded on opposite surfaces of the insulation substrate. In the electronic unit using such thick copper double-sided substrate, there is no established technique for accomplishing efficient heat radiation.
The present invention is directed to providing an electronic unit having a double-sided substrate in which metal plates are bonded on opposite surfaces of an insulation substrate and also allowing efficient heat radiation.